Berlin 2012 – wissenschaftliches Programm

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DF: Fachverband Dielektrische Festkörper

DF 16: Dielectric surfaces and interfaces

DF 16.1: Vortrag

Donnerstag, 29. März 2012, 11:40–12:00, EB 107

Resistive switching of Nb-doped SrTiO₃ single crystals — •Christian Rodenbücher, Krzysztof Szot, and Rainer Waser — Peter-Grünberg-Institut 7, Forschungszentrum Jülich, 52425 Jülich

The resistive switching effect in SrTiO₃ can be understood as an insulator to metal transition where a d-electron plays an important role which can be generated by creation of oxygen vacancies, electrodegradation or donor doping. In this talk we present the very surprising fact that Nb-doped SrTiO₃, although it is commonly regarded as a metallic material, can be switched. To clarify the nature of this phenomenon we investigated the crystallographic structure, the stoichiometry, the electronic structure and the transport by electrical measurements as well as by surface sensitive measurements like XPS, AFM and LEED which unquestionable reveal that switching occurs in a semiconducting surface layer which has greatly different properties than the metallic bulk. The stoichiometry and electronic structure of this surface layer can be dramatically altered by different preparation techniques like etching, leaching, heating in different atmospheres or Ar-bombardment. To get an insight in the nanoscopic origin of the switching, local conductivity AFM measurements were performed uncovering the highly local nature of the resistive switching which takes place in 10-30 nm big clusters which are present in the single crystal.